Regenerative and-gate circuit producing output during shaping-pulse input upon coincidence with but regardless of continuous presence of other input



Nov. 22, 1966 G. E. JENKINS 3,

REGENERATIVE AND-GATE CIRCUIT PRODUCING OUTPUT DURING SHAPING-PULSEINPUT UPoN COINCIDENCE WITH BUT REGARDLESS OF CONTINUOUS PRESENCE OFOTHER INPUT Filed March 11, 1964 OUTPUT k AND GATE Glenn E.Jenkins,

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United States Patent REGENERATIVE AND-GATE CIRCUIT PRODUC- ING OUTPUTDURING SHAPING-PULSE INPUT UPON COINCIDENCE WITH BUT REGARDLESS OFCONTINUOUS PRESENCE OF OTHER INPUT Glenn E. Jenkins, St. Paul, Minn.,assignor, by mesne assignments, to the United States of America asrepresented by the Secretary of the Army Filed Mar. 11, 1964, Ser. No.351,262 Claims. (Cl. 307-885) The invention relates generally to aregenerative shaper and more particularly to a means to shape and strobethe information output of a memory sense amplifier.

The need to produce a full width output pulse which is equal to thewidth of the strobe is presented when one is to shape and strobe theinformation output of a memory sense amplifier. Further, this fullwidthoutput pulse must be assured when a coincidence between the senseamplifier output pulse and the strobe pulse is established only at theleading edge of the strobe pulse. This must be done without the use ofany feedback transformers.

It is, therefore, an object of this invention to provide a regenerativeshaper suitable to shape and strobe the information output of a memorysense amplifier.

A further object is to provide a full width output pulse which is equalto the width of a strobe.

A still further object of the invention is to provide the above objectswithout the use of feedback transformers.

These and other objects and advantages of the present invention willbecome apparent from the following detailed description and from theaccompanying drawings, in which the single figure is a schematic circuitdiagram according to the invention.

In the drawing a transformer 2 has its primary winding 4 connected toreceive signals from a memory sense amplifier, not shown. Secondarywinding 6 is center tapped at tap 8. Two transistors 11 and 21 havetheir'base electrodes 13 and 23 connected to opposite ends of thesecondary winding 6 of transformer 2 by way of resistors 32 'and 34.Emitter electrodes 16 and 26 of transistors 11 and 21 are connected to acommon ground. Collector electrodes and 25 of transistors 11 and 21 aretied together by way of lead 36.

Transistor 41 has collector, emitter and base electrodes 45, 46 and 43.Emitter electrode 46 is tied to tap 8 of the transformer by lead 48. Thecollector electrode 45 is connected to a negative source of power atterminal 51 by way of resistor 53. A source of bias power at terminal 54is connected to emitter electrode 46 by way of a resistor 56. The baseelectrode 43 of transistor 41 is connected to junction 61.

A voltage divider network is formed between terminals 63 and 64. Thevoltage divider is madeup of the series connections of resistors 66, 67,and 68. A junction 69 is formed between resistors 67 and 68. A rectifier71 is connected between junction 69 and the lead 36 which ties thecollector electrodes 15 and 25 together.

An AND gate 72 is 'provided with two input terminals 73 and 74 and anoutput terminal 75. Transistors 84 and 85 have their collector-emittercircuit connected in parallel with each other and in series withresistor 87, terminal 88 and a source of voltage (E). The output of theAND gate is connected across output terminal 75 and ground.

The emitter collector circuits of transistors 11 and 21 are supplied bya source of negative voltage at terminal 90 by way of resistor 92. Thesource of voltage at terminal 90 is further connected to the inputterminal 74 of the AND gate by way of filter network 97. A source ofbias voltage at terminal 93- is connected to input terminal 74 of theAND gate 72 by way of resistor 95.

A source of strobe pulses is connected to the input terminal 73 of theAND gate by way of filter circuit 100. Bias voltages connected atterminals 101 and 102 are in circuit with input terminal 73 by way ofresistors 104 and 106.

The output terminal of the AND gate is connected to junction 69 by arectifier 110. All the sources of voltages have their other terminalconnected to a common ground.

Inthe absence of an input signal from the sense amplifier and assumingthe strobe pulse is not being applied to the input 73 of the AND gateand, therefore, to the base of transistor the condition of the circuitis as follows: transistors 84 and 85 of the AND gate will be onresulting in an output voltage level of approximately zero volts outputof the AND gate as all of the voltage of the source at terminal 88 willbe absorbed by resistor 87. Junction 69, being fixed to the output ofthe AND gate by diode 110, will be held at approximately the same level.The emitter follower, transistor 41, applies a reverse bias level(determined primarily by the value of the threshold voltage at terminal63) to transistors 11 and 21.

If an input signal of sufficient amplitude to turn on transistor 11 or21 (the determining factor being the polarity of the memorysense-amplifier signal) is applied to transformer 2, then one input willbe applied to the terminal 74 of the AND gate 72. This will turn offtransistor 84.

Initiation of the strobe signal serves to provide the second input tothe AND gate; therefore turning off transistor 85 and enabling the gate.The output terminal 75 of the gate will now fall negative. Junction 69will follow the output until such time as it is clamped by rectifier 71at a level (approximately -1 volt) which will sustain transistors 11 and21 (whichever one was on) through the emitter follower circuit.

In the event the amplifier output signal is of a short duration aftercoincidence is established with the strobe pulse, the AND output issustained in the following manner. When the rectifier transistor (11 or21) starts to turn off, junction 69 will fall negative, and its finalnegative limit will be determined by the voltage divider network formedby resistors 66, 67 and 68 or the output level (whichever is lessnegative). However, the negative voltage change of the junction 69 willbe present at the base of transistors 11 and 21 by virtue of the emitterfollower 41. Thus, transistor 11 or 21, or both, will be driven on andsustain the input to the AND gate; therefore sustaining the AND gate aslong as the strobe pulse is present. The transistor 11 or 21 is held outof saturation during this time and thus provides a fast circuitrecovery.

At the termination of the strobe signal, the input to terminal 73 of thegate will no longer be present; therefore, turning on transistor 85 andcausing the output of the AND gate to fall to approximately zero volts.Junction 69 will follow the output voltage of the gate; thereforecausing the threshold voltage applied to transistor 41 to become morepositive resulting in reverse bias to transistors 11 and 21 will now beallowed to turn off; therefore resetting the system for another cycle ofoperation.

While the invention has been described with reference to a preferredembodiment thereof, it will be apparent that various modifications andother embodiments thereof will occur to those skilled in the art withinthe scope of the invention. Accordingly, I desire the scope of myinvention to be limited only by the appended claims.

I claim:

1. A regenerative shaper for gate circuits comprising in combination: anAND gate having first and second input circuits, and an output circuit;means for providing a strobe signal which is connected to said firstinput circuit of the AND gate; signal means connected to an inputcircuit of a control means; said control means having an output circuitconnected to the second input circuit o fthe AND gate; and meansconnecting said output 2. A regenerative shaper as set forth in claim 1,wherein said control means comprises two amplifiers each having an inputcircuit and an output circuit. v

3. A regenerative shaper as set forth in claim 2, wherein the outputcircuits of the amplifiers are connected in parallel with each other andin series with said second input circuit of the AND gate.

4. A regenerative shaper as set forth in claim 3 further comprising atransformer having a primary Winding-connected to said signal means andhaving a secondary winding connected in a series circuit with the inputcircuits of said amplifiers.

5. A regenerative shaper as set forth in claim 4, wherein saidamplifiers are first and second transistors each having emitter,collector and base electrodes.

6. A regenerative shaper as set forth in claim 5 further including athirdtransistor having emitter, collector and base electrodes; saidsecondary winding of said -trans former having a center tap connected tothe emitter electrode of said third transistor, having one end connectedto the base electrode of said first transistor and having another endconnected to the base electrode of said second transistor; the collectorelectrode of the third transistor being connected to one terminal of asource of DC. voltage; said source of voltage having a second terminalconnected to the emitter electrodes of both the first and secondtransistors; and a connection between the base electrode of the thirdtransistor and said means connecting the output circuit of the AND gateto the g control means.

7. A regenerative shaper for gate circuits comprising first and secondamplifier means each having an input circuit and an output circuit; anAND gate 'having first and second inputs and an output; a source ofstrobe pulses; a source of signal voltages; connections between thesignalvoltages and said input circuit of said first amplifier means;means connecting the output circuit of said first'amplifier means tosaid first input of said AND gate; connection means connecting theoutput circuit of said second amplifier to the input circuit of thefirst amplifier; further means connected between. the input of thesecond amplifier and the output of said AND gate; and connectionsbetween said source of strobe pulses and the second input of said ANDgate, so that said AND gate will have an output upon coincidence ofsignals on both of its inputs and will have the output for the entiretime of the strobe pulse regardless of the time ofa signal from saidsource of signal voltages.

8. A regenerative shaper as set forth in claim 7 further comprising asource of bias voltage connected to the input circuit of said secondamplifier; said bias voltage being of such magnitude that when there isan output from the AND gate there will be an output from the outputcircuit of said first amplifier.

9. A regenerative shaper as set forth in claim 8, wherein said furthermeans connected between the input of the second amplifier and the outputof said AND gate is a rectifier.

10. A regenerative shaper comprising in combination a source of signalvoltages; a transformer having a primary winding and a center tappedsecondary winding; said source of signal voltages being connected acrosssaid primary winding; first, second and third transistors each having anemitter, collector and base electrodes; the base electrodes of saidfirst and second transistors being connected to opposite ends of saidsecondary winding of the transformer; the emitter electrode of saidthird transistor being connected to a center tap on the secondarywinding; a source of voltage connected to supply the collector-emitterelectrodes of said third transistor; means connecting the emitterelectrodes of said first and second transistors of each other by way ofa common ground connection; a first rectifier; both the collectorelectrodes of said first and second transistors being connected to oneside of said rectifier; a source of voltage connected to supply thecollector-emitter electrodes of said-first and second transistors;first, second and third resistors connected to each other in a seriescircuit and forming a first junction between said first and secondresistors and a second junction between said second and third resistors;a source of voltage connected across saidseries circuit; saidfirst-junction being connected to the base electrode of said thirdtransistor; said second junction being connected to other side ofsaidrectifier; a source of strobe pulses; an AND gate having first andsecond input terminals and an output .terminal; connections between thesource of strobe pulses References Cited by the Examiner UNITED STATESPATENTS 3,060,325 10/1962 Vinal 307 ss.5 3,192,404 6/1965 Jenkins 307ss.s

ARTHUR GAUSS, Primary Examiner. J. HEYMAN, Assistant Examiner.

1. A REGENERATIVE SHAPER FOR GATE CIRCUITS COMPRISING IN COMBINATION: ANAND GATE HAVING FIRST AND SECOND INPUT CIRCUIT, AND AN OUTPUT CIRCUIT;MEANS FOR PROVIDING A STROBE SIGNAL WHICH IS CONNECTED TO SAID FIRSTINPUT CIRCUIT OF THE AND GATE; SIGNAL MEANS CONNECTED TO AN INPUTCIRCUIT OF A CONTROL MEANS; SAID CONTROL MEANS HAVING AN OUTPUT CIRCUITCONNECTED TO THE SECOND INPUT CIRCUIT OF THE AND GATE; AND MEANSCONNECTING SAID OUTPUT CIRCUIT OF THE AND GATE TO THE INPUT CIRCUIT OFSAID CONTROL MEANS, SO THAT SAID AND GATE WILL HAVE AN OUTPUT UPONCOINCIDENCE OF SIGNALS ON BOTH OF ITS INPUT CIRCUITS AND WILL HAVE THEOUTPUT FOR THE ENTIRE TIME OF THE STROBE SIGNAL REGARDLESS OF THE TIMEOF A SIGNAL FROM SAID SIGNAL MEANS.